Customer configured DNS for cloud platforms AWS, Azure and GCP

enhancements/installer/aws-custom-dns.md → enhancements/installer/cloud-custom-dns.md

@@ -1,5 +1,5 @@
 ---
-title: custom-dns
+title: cloud-custom-dns
 authors:
   - "@sadasu"
 reviewers: 
@@ -194,6 +194,22 @@ this information to generate the CoreDNS CoreFile.
 
 ### API Extensions
 
+1. A new ConfigMap called `lbConfigforDNS` is created by the Installer. It can
+be created in any namespace but we are choosing to create it in the same
+namespace as the CoreDNS pods. Hence, the namespace name would be constructed
+as: openshift-$platform_name-infra
+
+```yaml
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: LBConfigforDNS
+  namespace: openshift-aws-infra
+data:
+  internal-api-lb-dns-name: "abc-123"
+  external-api-lb-dns-name: "xyz-456"
+```
+
 1. The AWSPlatformStatus within the PlatformStatus field of the Infrastructure
 ConfigResource (CR) is updated to contain all the DNS config required for the
 in-cluster CoreDNS solution. This same CR is available to the user post a
@@ -244,7 +260,6 @@ too. The validation for this config will disallow this value being `Enabled` in
 platforms that currently do not support it.
 
 ```yaml
----
 apiVersion: apiextensions.k8s.io/v1
 kind: CustomResourceDefinition
 metadata:
@@ -284,19 +299,61 @@ Infrastructure CR. Here is the update for platform AWS.
 // AWSPlatformSpec holds the desired state of the Amazon Web Services infrastructure provider.
 // This only includes fields that can be modified in the cluster.
 type AWSPlatformSpec struct {
-	// serviceEndpoints list contains custom endpoints which will override default
-	// service endpoint of AWS Services.
-	// There must be only one ServiceEndpoint for a service.
-	// +optional
-	ServiceEndpoints []AWSServiceEndpoint `json:"serviceEndpoints,omitempty"`
+        // serviceEndpoints list contains custom endpoints which will override default
+        // service endpoint of AWS Services.
+        // There must be only one ServiceEndpoint for a service.
+        // +optional
+        ServiceEndpoints []AWSServiceEndpoint `json:"serviceEndpoints,omitempty"`
 
         // customDNS indicates if the customer is providing their own DNS
         // solution inplace of the default provided by the underlying platform.
-	// Its value is set by the Installer and can have 2 possible values: 
-	// "Enabled" and "Disabled" with "Disabled" being the default.
+        // Its value is set by the Installer and can have 2 possible values: 
+        // "Enabled" and "Disabled" with "Disabled" being the default.
         CustomDNS string ``json:"customDNS,omitempty"`
 }
 ```
+
+4. The AWSPlatformStatus within the PlatformStatus field of the Infrastructure
+ConfigResource (CR) is updated to contain all the DNS config required for the
+in-cluster CoreDNS solution. This same CR is available to the user post a
+successful cluster install, to configure their own DNS solution.
+
+```go
+type AWSPlatformStatus struct {
+        <snip>
+        // AWSClusterDNSConfig contains all the DNS config required to configure a custom DNS solution.
+        // +optional
+        AWSClusterDNSConfig *ClusterDNSConfig `json:"awsClusterDNSConfig,omitempty"`
+
+        <snip>
+
+}
+
+type ClusterDNSConfig struct {
+        // APIServerDNSConfig contains information to configure DNS for API Server.
+        // This field will be set only when the userConfiguredDNS feature is enabled.
+        APIServerDNSConfig []DNSConfig `json:"apiServerDNSConfig,omitempty"`
+
+        // InternalAPIServerDNSConfig contains information to configure DNS for the Internal API Server.
+        // This field will be set only when the userConfiguredDNS feature is enabled.
+        InternalAPIServerDNSConfig []DNSConfig `json:"internalAPIServerDNSConfig,omitempty"`
+
+        // IngressDNSConfig contains information to configure DNS for cluster services.
+        // This field will be set only when the userConfiguredDNS feature is enabled.
+        IngressDNSConfig []DNSConfig `json:"ingressDNSConfig,omitempty"`
+}
+
+
+type DNSConfig struct {
+       // recordType is the DNS record type.
+       RecordType  string `json:"recordType"`
+
+       // lBIPAddress is the Load Balancer IP address for DNS config
+       LBIPAddress string `json:"lbIPAddress"`
+}
+
+```
+
 ### Implementation Details/Notes/Constraints [optional]